The embodiments described herein relate generally to condition monitoring of systems and equipment, and more particularly, to a method and system for use in condition monitoring of turbomachines.
At least some known turbomachines, i.e., gas turbine engines compress air via a plurality of rotatable compressor blades and ignite a fuel-air mixture in a combustor to generate combustion gases that are channeled through rotatable turbine buckets via a hot gas path. Also, at least some other known turbomachines, i.e., steam turbine engines channel steam through rotatable buckets via a steam path. Such known turbomachines convert thermal energy of the combustion gas stream and steam to mechanical energy used to rotate a turbine shaft. Output of the turbomachines may be used to power a machine, for example, an electric generator, a compressor, or a pump.
Many known compressor blades and turbine buckets are manufactured via processes that facilitate production of such blades and buckets with consistent material properties between like units thereof. However, slight material variations in the blades' and buckets' material properties may be present and are difficult to detect. Once these blades and buckets are placed in service, these minute differences start creating variations in the remaining useful life (RUL) of the blades and buckets.
At least some known maintenance repair processes for turbomachine components such as blades and buckets use standardized inspection and repair methods that are applied to all similar pieces of equipment to process the equipment through a standardized workscope. Such standardized workscopes may include turbomachine disassembly, extensive inspections, and corrective repair procedures that are applied to each component regardless of the actual condition of each component. For example, a component model that is constructed to predict life for the component may determine a replacement schedule and these values are used to schedule replacements. As a result, components having little or no defects may be processed with a similar expenditure of resources as those components having significant defects, including unnecessary replacement. This expenditure of resources is considered to be suboptimal from a financial perspective.
Also, at least some known maintenance repair processes for turbomachine components may include uncertainties of results for inspections that include standard non-destructive examination (NDE) and subsequent data analysis. For example, many known NDE processes/analyses do not provide adequate correlations of crack-growth data, including crack-growth rates, as a function of creep and creep-fatigue. In addition, there are few, if any, mechanisms to characterize crack-growth rates to specific components. Therefore, it is difficult to determine a RUL of a component undergoing progressive creep. Creep is estimated by measuring dimensions of the components and tracking changes of the dimensions over time. Record keeping practices are not standardized and frequently, due to uncertainties regarding original dimensions of the components and subsequent measurements, accurate determinations of creep are difficult to make.
Further, at least some known measurement systems for operating turbines and compressors include measurement instruments coupled to the compressor blades and turbine buckets. These systems typically require extensive wiring, modifications to the blades and buckets to accommodate the wiring, and complicated slip ring configurations, that are necessary due to the rotational operation of the monitored components, to transmit measurement data from the blades and buckets to an external data storage and analysis unit. Therefore, such systems increase construction and maintenance costs.